The Effects of STW 5-II on Duodenal Mucosa and Symptoms in Functional Dyspepsia

Inclusion Criteria: * Patients ≥18 years newly to be treated with an FD/PDS diagnosis (Rome IV clinical criteria). * Newly to be treated patients are defined as patients currently not on any ongoing treatment for FD (including OTC medication) for the last 2 weeks. Medications such as PPI or others that may affect GI function and symptom should be stopped prior the trial (min 4 weeks). See list of forbidden medication. * Male or female using contraception or postmenopausal * Witnessed written informed consent * Capable to understand and comply with the study requirements Exclusion Criteria: Inclusion criteria: * Patients ≥18 years newly to be treated with an FD/PDS diagnosis (Rome IV clinical criteria). * Newly to be treated patients are defined as patients currently not on any ongoing treatment for FD (including OTC medication) for the last 2 weeks. Medications such as PPI or others that may affect GI function and symptom should be stopped prior the trial (min 4 weeks). See list of forbidden medication. * Male or female using contraception or postmenopausal * Witnessed written informed consent * Capable to understand and comply with the study requirements Exclusion criteria: * Major active somatic or psychiatric condition that may explain dyspeptic symptoms (stable dose of single antidepressant allowed for psychiatric indication, no limitation for other indications) Predominant symptoms of gastro-esophageal reflux disease (GERD) or irritable bowel syndrome (IBS) * Chronic ppi use. No PPI use for at least the prior 4 weeks before entering the trial- History of major abdominal surgery (except for appendectomy, cholecystectomy or splenectomy) * History or presence of diabetes mellitus type 1 \& type 2, coeliac disease or inflammatory bowel disease * Active malignancy * Known HIV, HBV or HCV infection * Significant alcohol use (\>10 units/weeks) * Females pregnant or lactating * Hypersensitivity against ingredients of STW 5-II or placebo (see annex) * Abnormal baseline laboratory blood values